Privacy Policy — Day One
Effective date: September 22, 2026
1. Introduction
Day One ("the App") is a nicotine-cessation app published by Reno Labs, LLC ("we", "us", "our"). The App is designed to help you reduce and quit nicotine consumption by tracking your progress, showing a withdrawal-symptom timeline, visualizing recovery, and providing craving-management tools. This policy explains what information the App handles and how.
The short version: Day One has no user accounts and no servers of our own. Most data you enter stays on your device. We use two third-party tools — PostHog (analytics) and RevenueCat (subscriptions) — to process a stable pseudonymous identifier, product-interaction data, and subscription lifecycle data. We do not track you across other apps or websites, and we do not sell your data.
2. Information We Collect
2.1 Information you provide
To use the App you enter information such as your quit date, the type of nicotine product you use, your estimated cost and consumption, and the puffs or cravings you log. This information is stored locally on your device using Apple's on-device database. We do not receive or store a ProfileSnapshot, quitReasonCustom, trigger free text, HealthKit data, or contact information on any server we operate. You do not create an account, and we do not ask for your name, email, or phone number to use the App.
2.2 Information collected by third-party services
The App includes two software development kits (SDKs) that collect limited data on our behalf:
| Service | Data it collects | Purpose | Linked to you? | Used to track you? |
|---|---|---|---|---|
| PostHog (analytics & diagnostics) | A stable, randomly generated pseudonymous user ID stored in synchronizable iCloud Keychain; product-interaction events, feature-use counts and durations, onboarding step completion, selected product type, experiment assignment, and subscription state; crash and diagnostic data; and the iOS vendor identifier. The service also receives network information such as IP address. The release candidate removes raw quit dates, consumption and spend amounts, dependency answers and scores, NRT dose values, and persistent NRT-status properties from app-authored analytics. Earlier versions had different collection practices; these changes do not delete records already held by our processors. Raw profile snapshots, custom quit-reason text, trigger free text, HealthKit readings, and contact information are not intended analytics inputs. | Understand how the App is used, link subscription-lifecycle analytics to product interactions, improve the App, and detect and fix crashes. | Yes — the data is attached to the stable pseudonymous user ID, which persists across reinstalls and the user's devices. | No |
| RevenueCat (subscriptions) | Subscription lifecycle data, including product ID, entitlement, period type, and cancellation or billing reason when RevenueCat supplies it; purchase history; and a RevenueCat app-user identifier. RevenueCat receives the reserved $posthogUserId attribute to associate subscription-lifecycle analytics with the same stable pseudonymous ID used by PostHog. RevenueCat does not receive raw profile snapshots, custom quit-reason text, trigger free text, HealthKit data, or contact information from the App. |
Manage subscriptions, validate App Store receipts, prevent fraud, unlock paid features, and analyze subscription lifecycle events. | Yes — subscription lifecycle data is associated with the stable pseudonymous identifier through the RevenueCat/PostHog linkage. | No |
Health-related analytics: PostHog receives cessation progress and craving outcomes, selected nicotine-product and quit-reason categories, and nicotine-replacement feature actions. These events are linked to the stable pseudonymous identifier and used for analytics. They are health-related information even though HealthKit readings stay on your device.
Neither service is used for advertising or for tracking across other companies' apps, websites, or offline properties, and the App does not use Apple's App Tracking Transparency tracking. Our privacy manifest declares NSPrivacyTracking = false.
2.3 Device permissions
Day One optionally requests notifications for local reminders and craving-completion alerts. Live Activities have a separate iOS setting and do not require notification permission. The in-app timer works when Live Activities are off. If you choose the resting-heart recovery feature, the App requests read access to resting heart rate in Apple Health. It does not write Health data or send HealthKit readings to our analytics services. Day One does not request camera, photo-library, location, contacts, or microphone access. You can manage permissions in iOS Settings and Apple Health.
2.4 Purchases through Apple
Subscriptions are sold and processed by Apple through the App Store. Apple handles your payment information under Apple's Privacy Policy; we never see your payment-card details.
3. How We Use Your Information
- To provide the App: your locally stored entries power your streak, money-saved counter, withdrawal timeline, and recovery visuals.
- To manage subscriptions: RevenueCat verifies purchases, processes subscription lifecycle events, and unlocks paid features. The optional Day-30 Maintenance offer is available only to eligible legacy weekly subscribers and requires their confirmation.
- To improve the App: PostHog product-interaction analytics and the RevenueCat/PostHog pseudonymous linkage help us understand subscription lifecycle events in the context of App use.
- To keep the App working: crash and diagnostic data help us find and fix bugs.
4. Third-Party Services
- PostHog — product analytics, subscription-lifecycle analytics through the shared stable pseudonymous ID, and crash reporting. posthog.com/privacy
- RevenueCat — subscription management, receipt validation, and subscription-lifecycle processing associated with the same stable pseudonymous ID. revenuecat.com/privacy
- PostHog product development: its current policy permits use of aggregated or de-identified customer content for its own product and model development unless a contractual exemption or customer opt-out applies. We have not confirmed the applicable Day One setting and have not established whether this use applies to Day One's records.
- Apple — App Store purchases and iCloud backup (see below). apple.com/legal/privacy
5. Data Storage and Security
Most information you enter lives in an on-device database. The product-interaction and subscription properties described above are sent to PostHog. To protect your streak from accidental loss, your quit date and remaining streak freezes are backed up to your own private iCloud account using Apple's iCloud key-value storage. That backup is governed by Apple's privacy terms and is not accessible to us. Analytics and subscription records are held by PostHog and RevenueCat under their respective policies. A change to the App's collection behavior does not delete previously collected records; you can contact us about deletion as described below.
6. Your Rights
6.1 European Economic Area, UK & Switzerland (GDPR)
If you are in these regions, you have the right to access, correct, erase, restrict, or object to the processing of your personal data, and the right to data portability. We do not hold user accounts, but analytics and purchase records are linked to persistent pseudonymous identifiers. To exercise any right, contact us at the address below and we will respond within the timeframes required by law. Our legal basis for analytics and crash reporting is our legitimate interest in operating and improving the App; for subscriptions it is performance of a contract.
6.2 California (CCPA/CPRA)
California residents have the right to know what personal information is collected, to request deletion, and to opt out of the "sale" or "sharing" of personal information. We do not sell or share your personal information, and we do not use it for cross-context behavioral advertising. To make a request, contact us below.
7. Children's Privacy
Day One is intended for adults seeking to quit nicotine. Its current U.S. App Store age rating is 17+; ratings can vary by region. It is not directed to children under 13, and we do not knowingly collect personal information from children. If you believe a child has used the App, contact us and we will assist.
8. Deleting Your Data
Day One has no account to delete. To remove the data you entered, delete the App from your device; to remove the iCloud streak backup, sign in to iCloud settings on your device and remove Day One's data. To request deletion of analytics or subscription records held by our processors, email us and we will arrange it.
9. Changes to This Policy
We may update this policy from time to time. When we do, we will revise the "Effective date" above and post the new version at this URL. Material changes will be reflected in the App where appropriate.
10. Contact Us
Reno Labs, LLC
Email: support@renolabshq.com